The present invention relates to blind fasteners including a pin and a sleeve and installed by the application of a relative axial force between the pin and sleeve.
The present invention relates to blind fasteners and more particularly to blind fasteners including a pin (or spindle) and a sleeve with the pin having a head segment adapted to move into the shank of the sleeve at the blind side to form an enlarged tulip shaped blind head having a clamp support and lock section at the blind side and with the pin and sleeve having a second, mechanical lock structure at the opposite end for locking the pin and sleeve together,
In many blind fasteners blind heads are formed of an enlarged tulip shape. Examples of such blind fasteners can be seen in U.S. Pat. No. 4,863,325 for Two Piece Blind Fastener With Lock Spindle Construction issued on Sep. 5, 1989 to Walter Smith, U.S. Pat. No. 4,627,775 for Blind Fastener With Grip Compensating Means issued on Oct. 9, 1986 to Richard Dixon, and U.S. Pat. No. 4,405,273 issued Sep. 20, 1983 to Ruhl et al for Blind Fasteners. This is in contrast to other blind fasteners in which blind heads are formed of a bulbed type. Examples of such blind fasteners can be seen in U.S. Pat. No. 4,784,551 for Fastening System And Method For Flush And Protruding Head Blind Fasteners issued on Nov. 15, 1988, to James Kendall and U.S. Pat. No. 5,603,592 for High Strength Blind Bolt issued on Feb. 18, 1997 to Sadri et al. The ""592 patent shows a combination bulb and tulip type blind head. See also the MAGNA-BULB(copyright) type fastener shown in FIGS. 7-9.
The present invention is directed to a unique form of blind fastener for forming an enlarged tulip shaped blind head with a clamp support and lock section.
In the present invention a blind fastener (including a pin and a sleeve) is provided with the pin having a pin shank with a head segment at one end and with the sleeve having a sleeve shank and a sleeve head at one end. The head segment of the pin has an enlarged shear ring adapted to be moved into the shank of the sleeve at the blind side to form an enlarged tulip shaped blind head. The head segment of the pin has a retention portion having a plurality of retention grooves and crests following the shear ring. The shear ring is adapted to shear at a preselected magnitude of relative axial force after the blind head is fully formed and the shear ring is located adjacent the inner or blind side of the workpieces. Now the rest of the pin will continue to be pulled into the sleeve with the number of retention grooves and crests being moved through the shear ring depending upon the overall thickness of the workpieces. The shear ring will be engaged with one of the retention grooves and crests to form, with the adjacent, enlarged portion of the sleeve shank, the blind head having a clamp support and lock section at the blind side. At the same time the movement of the pin has continued until stop shoulders of the pin and sleeve are engaged and a mechanical lock is formed at the opposite end after which the pin will be severed at a breakneck groove to remove a pull portion from the shank of the pin. As will be seen the fastener of the present invention provides a blind head of a substantially uniform high strength over a typical, substantial grip range or range of total thickness of workpieces being secured together.
It should be noted that a blind fastener having a shear ring in combination with a plurality of retention grooves to form a blind head has been utilized in a blind fastener made by Huck International, Inc. and sold under the registered trademark MAGNA-BULB(copyright). There, however, the shear ring does not enter the sleeve to form an enlarged tulip shaped blind head but, as noted, rather forms a bulb type blind head adjacent the inner or blind side surface and in addition, as will be seen, the retention groove structure is also somewhat different. Other significant differences will also be seen.
One form of the blind fastener of the present invention has a unique protruding sleeve head structure with engaging surfaces providing a relatively high level of stress concentration with the engaged surfaces of the workpieces being secured together. This provides a high level of resistance to slippage between the workpieces and the installed fastener. Such a construction then lends itself to use in applications where there is some gap between the workpiece openings and the installed fastener.
Thus it is an object of the present invention to provide a novel blind fastener, including a pin and a sleeve, and in which the pin and sleeve have a structure for forming an enlarged, tulip shaped blind head with a lock between the pin and sleeve at that end.
It is another object of the present invention to provide a blind fastener having a unique structure for forming a blind head.
It is still another object of the present invention to provide a blind fastener having a unique structure for forming an enlarged, tulip shaped blind head with a clamp support and lock section at that end.
It is still another object of the present invention to provide a blind fastener having a unique structure for forming an enlarged, tulip shaped blind head with a clamp support and lock section at that end and being of a generally uniform configuration and high strength over a substantial grip range.
It is also an object of the present invention to provide a blind fastener having a unique protruding sleeve head for providing a high level of resistance to slippage between the workpieces being secured together and the installed fastener.
It is a general object of the present invention to provide a new and improved blind fastener.
Other objects, features, and advantages of the present invention will become apparent from the subsequent description and the appended claims, taken in conjunction with the accompanying drawings.